中文摘要：

采用二甲基乙酸三硫代碳酸酯（S，S’-bis（α，α’-dimethylacetic acid）trithiocarbonate）作为链转移剂、4，4＇-偶氮二（4-氰基戊酸）（ACVA）作为引发剂，用可逆加成一断裂链转移自由基聚合（RAFT）的方法合成不同分子量的羧基封端的聚N-乙烯基吡咯烷酮（PVP）．采用H—NMR和FTIR对聚合物结构进行表征，采用粘度法测定聚合物的分子量，研究聚合温度、反应时间和链转移剂浓度对PVP分子量和单体转化率的影响．结果表明：提高反应温度有利于提高单体转化率，单体转化率与PVP分子量呈线性增加关系，在保证单体转化率的情况下，随着RAFT试剂用量增加，PVP分子量降低．

英文摘要：

A series of carboxyl-terminated PVP with different molecular weight was synthesized via re- versible addition-Fragmentation chain transfer （RAFT） polymerization, in which S, S＇-bis（a, a＇-dimethyl- acetic acid） trithiocarbonate was used as chain transfer agent and 4,4＇-azo-di（4-cyanopyridine pentanoic acid） （ACVA） was used as initiator. The structure of prepared polymers was characterized with H nuclear magnetic resonance （H-NMR） and Fourier transformed infrared spectroscopy （FTIR） and the molecular weight was determined by means of ubbelohde viscometry to investigate the impact of synthesis condition, such as temperature, time and concentration of CTA, on molecular weight and monomer conversion rate of PVP. The results showed that the conversion rate of monomer would increase with the increase of poly- merization temperature, PVP molecular weight would decrease linearly with monomer conversion rate, with the increase of amount of RAFT agent, the molecular weight would decrease in the case of unchanged monomer conversion rate.